Method of making spherical coils for variometers



E. E. COMBS 2,455,355

METHOD OF MAKING SPHERIQAL COILS FOR VARIOMETERS Dec. 7, 1948.

Filed Sept. 24, 1945 FIG.2

FIG.3

FIG.|

INVENTOR.

EDWARD E COMES I Patented Dec. 7, 1948 METHOD OF MAKING SPHERICAL COILS FOR VARIOMETERS Edward E. Combs, Long Branch, N. .1.

Application September 24, 1945, Serial No. 618,382

1 Claim.

(Granted under the act of March 3. 1883, as amended April 30, 1928; 370 O. G. 757) The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to a method of making spherical coils for variometers, and this application is a continuationin-part of the applica tion filed September 6, 1944, entitled Spherical coils for variometer, Serial No. 552,859, issued as Patent 2,441,564 on May 18, 1948.

Although the advantages of spherical coils are well known in the art, their use has been somewhat limited because no simple manufacturing methods were available, and, as a consequence, the majority of variometers used cylindrical rotors.

It is therefore an object of this invention to provide a method of making spherical radio coils having improved structural and electrical features.

In the drawings:

Fig. 1 is an isometric view of a coil frame equipped with ceramic pieces for supporting wire, the ceramic pieces being mounted on a ring made of plastic material,

Fig. 2 is a side view of a jig or form having a coil wound thereon;

Fig. 3 is a perspective view of a wire holder which is used for transferring the wound wire from the jig illustrated in Fig. 2 onto the coil frame illustrated in Fig. 1.

Fig. 4 is a side view of the coil frame illustrated in Fig. 1 with the wire wound upon it.

It is known in the radio art that uses of the variometer are encountered which subject the coils to such heavy loads that the current-carrying wire reaches sufiiciently high temperature either to melt or carbonize the wire supporting elements made of plastics. The use of plastics for making the wire supporting elements is always desirable because of their resistances to shock. However, when the radio coils are heated to such high temperatures, the use of the plastics for supporting the wire is impossible and materials which can withstand high temperatures, such as ceramic materials, must be used in their stead. The prior art has known the use of ceramic bridges for supporting the coil; however, the coils with the ceramic bridges invariably used ceramic disks or ceramic rings for supporting them,

which rendered the entire coil frame very brittle, and not capable of resisting severe mechanical shocks. Fig. 1 shows a coil frame in which the bridges are made of ceramic material, while the ring supporting the bridges is made of [plastic material, the resilient properties of the plastic material making the coil frame more suitable for resisting very severe mechanical shocks.

Referring to Fig. 1, the wire supporting bridges [0 are made of ceramic material, the bridges being mounted radially on a ring 12 made of plastic material. The outer surfaces l3 of the bridges are grooved for holding the wire and the inner ends of the same bridges are provided with extensions l4 and I6 which fit into recesses l5 pro vided for this purpose in ring l2. To hold the ceramic bridges radially to the ring, registering apertures I8 are formed in both to receive pins I 9. The latter are preferably of non-brittle synthetic plastic material, the resilience of which further improves the resistance of the coil frame to mechanical shock. A two-piece shaft 29 and 22 of the coil is mounted on ring I! by means of threaded ends 24 and nuts 26 (only one end is visible in the figure). The wound wire is connected to the shaft by means of lugs 28.

The advantage of the structure illustrated in Fig. 1 resides in the fact that ring [2 is mode of a plastic material, thus providing a resilient support for the ceramic pieces, the resiliency of the ring and the resiliency of the connection between the ring and the bridges contributing markedly to the ability of the coil to absorb severe mechanical shocks. In the prior art ring l2 was made of ceramic materials, which produce a very brittle frame not capable of absorbing severe mechanical shocks. The mechanical shocks are trans ferred to the surfaces interconnecting the bridges with the ring which produces cracking of the joints. This is not the case in the disclosed structure because the ring acts as a shock-absorbing medium. When the shocks are transmitted through the shaft pieces 20 and 22, the shock is absorbed to a very large extent by the ring and is transferred to the bridges in a sufficiently subdued form so as to prevent cracking of the ceramic pieces at the joints. When the ring is made of the ceramic material it ordinaril cracks, resulting in the collapse of the entire coil.

In order to mount a coil on the coil frame illustrated in Fig. 1, a coil form 29!] illustrated in Fig. 2 is used. It consists of a spherical metal form 2H6 slidingly mounted on a mandrel 202, the mandrel being mounted in a lathe which revolves the form when a wire 204 is wound upon it. A clamp 206 is provided which is used for clamping the free end of the wire, and after the wire has been clamped, the form is rotated and the wire is wound on the form, the wire following grooves 208 provided for this purpose on the form. After the form has been completely wound the rotation of the form is stopped, and the opposite end of the wire is clamped by means of a clamp 2H1 similar to clamp 206. The wire is then cut off" and the next step consists of transferring the Wire wound on form 20 onto the'wireholder or holding means shown in Fig. 3

The wire holder consists of four projections 300, 302, 304, and 306 joined together at 308, the

inner surfaces of the projections being provided with grooves 3I0, 3I2 for holding the Wire. Only one wire holder is illustrated in Fig. 3, but to accomplish the transfer of the wire from the form 200, two wire holders are used. simultaneously, the second holder being identical to the one illustrated in Fig. 3. After removing; form' 200 from the mandrel, the two holders are slipped over form 200, which they fit snugly, clamps 2'06, 2 l 0 are removed, and the wire is cut' in the middle of the coil. Because of the springing action of the wire, it unwin'd's itself slightly, this unwinding of the wire transfersit to the holders. The holders are then removed fromform 200; and are placed on the frame illustrated Fig. 1.

The outer free ends 410 and N2 of the wire" are then clamped to the ceramic brid'ges ID by means of clamps 400*, 402,- as illustrated in Fig. 4, and after the outer ends have been thus secured to the ceramic bridges, the inner ends 4%, i 08 of the wire are pulled tightly against the bridges,

thus transferring the wire from the holders onto cases the variometer structure may be such that connection of the outer ends 410 and M2 to the lugs must be performed within the vai iom'eterafter the spherical coil has been'inserte'd i nt'a stator. Ineither case the fin al connections are the same. 7

In describing theforegoing method, it has be'en stated that the entire coil is wound on the mandrel' illustrated in Fig. 2 and the wound wire is then cut in the middle, after which the coil parts are transferred onto the holders illustrated in Fig. 3. When especially large coils are" wound and the wire used for the coils is very heavy or is in the form of a hollow coppertubirig, cutting of the wire on the form in such cases is not convenient, and it' is simpler to wind a coil on half of form 200, whereupon the Wire is firaris'-' ferred onto the wire holder". Another coil is then wound on the other half of the mentioned form and is transferred to a wire holder. When the two wire holders contain the two coils, the wire is transferred to the coil frame illustrated in Fig. 1 in a manner similar to that described previously in the specification. The advantage of this method resides in the fact that it is unnecessary to cut the wire when it is wound on the mandrel and it is more convenient to make the soldered joint 404. Making of the soldering connection is simplified because fairly long ends may be left at the end of the winding operation and because of this excess length it is more convenient to handle Wire during the soldering operation. Upon the completion of the soldering joint the excess wire is sawed off or cut off.

While the invention has been described with reference to several particular embodiments, it will be understood that various modifications of the apparatus shown may be made within the scope of the following claim.

I claim:

In a method of making a spherical radio c'oil winding a wire, in the forth of a coil, on a spherical form, fitting over said form, after the wire has been wound, two wire holders the interior hold.- ing surfaces of which are ofsph'erical contour and of such a diameter that the wire" can be e'xp'anded sufiiciently to clear the ridges of the wire'former,

transferring saidwire from saidform onto said holders by cutting said Wire approximately in the middle of the coil so as to obtain two approximately equal parts, allowing the wire to expand from said form into said holders, placing said wire holders over a sphericz'rlcoil frame, transferring said wire from the holders onto said frame b clamping the outer" ends of said Wire against said frame a'nd by pulling the cut ericls" of the wire until'the entire length of said wire engages said frame, and joining the cut ends of the wire together.

EDWARD E. COMES.

REFERENCES GITED he following references are of .record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,546,424 Wood July 21, 1925- l,636,1'78 Gargan July 19, 1927 2,013,764 Putnam Sept. 10, 1935 2,143,315 Hanson Jan. 10, 1939 2,394,028 Volsk Feb: 5, 1946 

